This paper presents a proof of controllability for a multibody mobile robot (e.g., a car pulling and pushing trailers like a luggage carrier in an airport). Such systems appear as canonical systems to illustrate the tools from differential geometric control theory required by nonholonomic motion planning. Three modeling steps are considered: geometric, differential, and control steps. The author derives the kinematic equations for four distinct multibody mobile robot systems: a convoy driven by 1) a unicycle, 2) a two-driving wheels vehicle, 3) a real car and 4) the first two bodies. He shows that these four control systems correspond to the same differential model, which is then used to give the same proof of controllability. Previous work proved the controllability of two-body systems and three-body systems. The main result of this paper is prove the controllability for a general n-body system